Effects of Climate Change on Co-Occurrences of Allergenic Pollen and Photochemical Air Pollutants in the United States

摘要

Ambient air quality has been substantially impacted by climate change over the past few decades. In fact, climate change critically affects both the atmospheric processes involved in the dynamics of air pollution systems and the dynamics of biogenic emissions including trees and grass pollens and fungal spores. Furthermore, the prevalence of Allergic Airway Disease (AAD) is growing globally, resulting in increased numbers of emergency department visits and hospitalizations. Clinical studies show that AAD can be exacerbated by the synergistic action of aeroallergens such as pollen and spores, and atmospheric pollutants such as ozone. Previous studies, involving data from nationwide observations of airborne pollen counts of selected plant species in conjunction with climatic factors, indicated that the start date and length of pollen season, the average peak value and the annual total of daily airborne pollen counts have been affected by the changing climate. The present study investigates co-occurrences of ozone exceedance and allergenic pollens across the contiguous United States (ConUS). Analyses of observed pollen counts and ozone concentrations at 58 pollen monitor stations were conducted. Also, emissions and concentrations of pollens in base years (2004) and future years (2047) were simulated with a customized version of CMAQ (the Community Multiscale Air Quality model) employing a grid with 36 km by 36 km horizontal resolution, while corresponding ozone concentrations at the same resolution for the above timeframes were conducted by a multi-university/agency consortium including USEPA. This study employed spatiotemporal correlation analysis to examine patterns of co-occurring ozone and pollen concentrations; the outcomes of this analysis provide information that can support development of strategies for managing health-impacts of co-occurring photochemical pollutants and aeroallergens.